This invention relates in general to coating by vapor deposition and to a new and useful multiple holder for substrates to be treated.
There are known various holding structures by which spectacle lenses are engaged by their edges and which, after receiving the load, may selectively be inserted into a cleaning or coating apparatus. However, problems arise recurrently with the failure of coating the entire surface of the substrates, up to the edges, because the retaining elements of the holders still cover small areas of the surfaces to be coated which, consequently, fail to become coated. This is a weighty drawback especially with spectacle lenses requiring not only a technologically satisfactory coating but also a perfect appearance.
Known are coating apparatuses in which the holders are shaped as planar plates having recesses for the substrate to be coated, with a plurality of such plates being inserted into a rotary structure to form together a spherical segment. Holders of this kind are generally suitable only for the respective coating apparatus, wherefore, prior to or after the coating, the substrates must usually be transferred to other supports which are suitable for the treatment in other apparatuses. This transfer represents additional time losses and costs in the process, which are not inconsiderable.
Since the individual substrates to be coated have varying sizes, frequently individual supports are employed which are adapted to the respective sizes and can be inserted into conformable holding structures which, in turn, are adapted to the apparatus in which the coating or other treatment is preformed. It will be understood that handling of such a system of supports or holders nested into each other is still rather expensive.